1. Field of the Invention
The present invention relates to a method of obtaining biofuels from watermelon seeds.
2. Description of the Related Art
Bioethanol is an eco-friendly alternative fuel extracted through fermentation of saccharide or cellulose fractions in plants. As such, bioethanol increasingly draws more attention for its usefulness as an additive in gasoline products, compared to existing biomethanol used as an additive in diesel products.
Since the 1970s, most studies in the development of bioethanol have been implemented in the United States and Brazil, as the main producers. In Brazil, production of bioethanol using sugar cane has been promoted as one of the national policy projects, and about 30% of overall fuel consumption for vehicles has been successfully replaced with bioethanol in 2004. In the United States, it was announced in the President's Annual State of the Union address to Congress in 2008, that oil consumption would be reduced by 20%, replacing oil consumption with the increasing use of alternative energy, such as bioethanol In addition, other countries including, for example, Japan, China, and other Asian nations, are also moving ahead with policies to expand bioethanol production. As such, with increased demand and interest in bioethanol throughout the world, bioethanol production output is gradually increasing.
After the oil crisis in the 1970s, research and development into bioethanol began as a part of an alternative energy development initiative and has mostly been executed with crop biomass obtained from corn, sugar cane, and/or wood-based biomass. Wood-based biomass as raw materials can be obtained from wood resources. In fact, Brazil has succeeded in the commercialization of bioethanol fuel based on the abundant cultivation and supply of sugar cane. Meanwhile, in the United States, plenty of commercial technologies to produce bioethanol utilizing abundant corn and/or wood resources have been accumulated.
However, with regard to crop biomass, ethical problems associated with utilizing invaluable food resources as fuel raw materials has recently been publicized and, in addition, disadvantages related to the production of bioethanol, using such crop biomass, has similarly been encountered with regards to the supply and demand of raw materials, and/or price competitiveness resulting from international grain prices rapidly increasing in early 2008.
Although resources for wood-based biomass have merit in increasing ethanol production yield, in that they are plentiful in nature, cellulose content, and hemi-cellulose content (i.e., the obtained biomass is at least 75%), the wood-based biomass has a physically and chemically rigid structure, compared to crop biomass, thus causing difficulties in chemical and/or enzymatic treatment approaches for the saccharification of cellulose and/or hemi-cellulose. Moreover, since wood-based biomass contains about 15 to 25% lignin, consisting of numerous hydrophobic aromatic compounds, high costs and complicated pre-treatments to remove the said lignin fraction may be required. Furthermore, forest degradation encountered in biomass production also accelerates global warming and causes environmental damage, in turn manifesting in problems with environmental ethics, such as violation of responsibilities related to eco-friendly fuel production.
Accordingly, in order to solve these ethical problems, while overcoming the energy (fuel) crises or exhaustion that mankind is facing, there is a strong need to ensure novel and highly efficient biomass resources capable of replacing existing crop biomass or wood-based biomass resources.